We've told you everything you need to know about 4G, but if you're thinking about switching networks when you get that 4G phone or modem, you might be basing it on who's faster. Here's how the networks stack up against one another.

Verizon just launched their 4G data network, joining Sprint and T-Mobile at the party. But what is…
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We mentioned the speeds each company is claiming in our 4G roundup, but the numbers weren't always the most trustworthy. PC World did some serious testing of Verizon, AT&T, T-Mobile, and Sprint's networks for both 3G smartphones and 4G modems, and the results were a bit surprising. T-Mobile ended up being the fastest on the smartphone end with 2.28 Mbps down, while Verizon came in last at less than half that. As far as USB modems went, it was very different: Verizon had by far the fastest speeds, hitting about 6.44 Mbps down and 5 Mbps up, while Sprint came in last—albeit close to T-Mobile and AT&T—at a bit more than 2 Mbps down and less than 1 Mbps up.

For both sets of devices, they tested the connections in 260 different locations across 13 different US cities, so they were pretty exhaustive, giving us confidence in the results.

Update: Many of you noted in the comments, correctly so, that PC World's methodologies were quite flawed and a bit misleading. They (and we) should have just labeled this "smartphone speeds", as oftentimes it was a networks 3G speeds that factored into the average. If they went to a location and a given network didn't have a 4G connection there (which Verizon doesn't have anywhere on its smartphones yet), they just used the 3G speed.

So, while the tests don't really show what they set out to show, they do still provide some valuable information: which networks are going to give you, on average, the fastest internet connection in a given city. We're still a little surprised how far down AT&T was on the list, boasting to be the nation's fastest network. As with all things technology, these statistics are likely to change more in the coming months, but if you went out and bought a phone now, this is what you'll get from a given provider.

Of course, there are a lot of other reasons to choose a given network, but these speeds may give you something else to think about as you inch closer to buying that new 4G phone. Hit the link to read more about the tests.